TOKYO -- Prime Minister Junichiro Koizumi's governing party won a landslide victory in general elections yesterday, as voters handed Japan's maverick leader a remarkable mandate to enact a new stage of changes in the world's second-largest economy.
The triumph, by a wider margin than expected, appeared to reflect backing for Koizumi's economic agenda, particularly the privatization of the $3 trillion postal service, as well as his vision for closer alignment with the United States.
His Liberal Democratic Party won its largest majority in the 480-seat lower house of parliament since 1986, winning at least 296 seats, a gain of 84. The LDP's smaller coalition partner, the Buddhist-led New Komeito, grabbed 34 seats.
The big loser was the opposition Democratic Party, which had hoped to seize power from Koizumi and had called for a pullout of Japan's noncombat troops from Iraq, with a withdrawal of US forces from Okinawa. Instead, the party won only 113 seats, down from 177.
While seen as a personal triumph for Koizumi, the new mandate is likely to continue a period of heightened tension in East Asia, particularly in Japan's relationship with China.
During Koizumi's four-year tenure, the two have sparred over rights to drill for natural gas in the East China Sea, and have engaged in a debate over Japan's perceived lack of contrition for war crimes.
Koizumi's victory came after his extraordinary makeover of the LDP, a traditional and nationalistic party that has ruled Japan for most of the post-World War II era. Last month, Koizumi, 63, known here as ''Lion Heart," purged his party of hard-liners who opposed his reform campaign. At the same time, he brought in women and younger candidates who backed his agenda for change.
''I have destroyed the old LDP," a victorious Koizumi told reporters last night. ''It has become reborn as a new party."
Koizumi focused the public debate largely on the postal service as a symbol of his move to overhaul Japan Inc.
Essentially the world's largest public bank, with a work force of 380,000, its huge reserves have long been used as a back door for old-guard LDP members to finance pork-barrel projects in some of their home constituencies. Postmasters -- jobs often passed from father to son -- have been used as unofficial campaign aides on Election Day.
While rural Japanese remain largely opposed to reforms, Koizumi's campaign stirred up record support for the LDP from young, urban, and unaffiliated voters, for whom the ruling party had long been anathema.
''I never voted before, but this time I came out to bet on Mr. Koizumi," said Daisuke Muramatsu, 24, an event planner in Tokyo. ''Koizumi is riding high. I like his resolute character and his aggressive attitude. These are Japan's biggest round of reforms since Meiji Restoration," in the 19th century.
''And I'd like to give Koizumi a chance to pull them off."
Koizumi, analysts say, is now likely to push his postal privatization package through the upper house, which rejected it last month. Koizumi does not have the authority to dissolve the upper house, so after the bill was defeated, he dissolved the lower house and called early elections. He is betting that upper house members will not ignore the support for change.
Armed with a massive support base in the lower house, Koizumi will need to ensure that those elected on his platform follow through with those plans, economists say. He will also have no excuses for not pushing other major changes, including revamping social security.
Though Koizumi has been accused of having moved too slowly on reform, economists credit his administration with making major progress on cleaning up Japan's bad loans from the 1990s. Bolder steps could further boost confidence in the economic recovery there.